Hydraulic speed modes for industrial machines

ABSTRACT

An industrial task machine includes a mechanical arm and a hydraulic actuator coupled to the mechanical arm to move the arm between a first position and a second position. A valve is in fluid communication with the hydraulic actuator for supplying fluid to the hydraulic actuator. A pump is configured to discharge fluid to the valve. A load sensing system is configured to determine a load pressure value associated with the mechanical arm. A control device is configured to permit selection of a normal mode or a speed adjustment mode. A speed adjuster is configured to receive an input from the control device, modify a margin pressure value in response to selection of the speed adjustment mode, and output the modified margin pressure value. A controller is coupled to the pump, the load sensing system, and the speed adjuster. The controller is configured to receive the load pressure value from the load sensing system and the modified margin pressure value from the speed adjuster, and adjust the fluid discharge from the pump based on both the load pressure value and the modified margin pressure value.

FIELD

Various exemplary embodiments relate to hydraulic control systems.

BACKGROUND

Many industrial machines, such as construction equipment, use hydraulicsto control various moveable implements. The operator is provided withone or more input or control devices operably coupled to one or morehydraulic actuators, which manipulate the relative location of selectcomponents or devices of the equipment to perform various operations.For example, backhoes often have a plurality of control levers and/orfoot pedals to control certain functions of a backhoe, such as aposition of a boom arm, a position of a dipper arm coupled to the boomarm, and a position of a bucket coupled to a dipper arm.

SUMMARY

According to an exemplary embodiment, an industrial task machineincludes a mechanical arm and a hydraulic actuator coupled to themechanical arm to move the arm between a first position and a secondposition. A valve is in fluid communication with the hydraulic actuatorfor supplying fluid to the hydraulic actuator. A pump is configured todischarge fluid to the valve. A load sensing system is configured todetermine a load pressure value associated with the mechanical arm. Acontrol device is configured to permit selection of a normal mode or aspeed adjustment mode. A speed adjuster is configured to receive aninput from the control device, modify a margin pressure value inresponse to selection of the speed adjustment mode, and output themodified margin pressure value. A controller is coupled to the pump, theload sensing system, and the speed adjuster. The controller isconfigured to receive the load pressure value from the load sensingsystem and the modified margin pressure value from the speed adjuster,and adjust the fluid discharge from the pump based on both the loadpressure value and the modified margin pressure value.

According to another exemplary embodiment, an industrial task machineincludes a frame and a plurality of movable implements coupled to theframe. Each implement individually moveable between a first position anda second position. The machine includes a plurality of hydraulicactuators, wherein at least one hydraulic actuator is coupled to each ofthe implements, and a plurality of valves, wherein at least one valve iscoupled to each hydraulic actuator. A pump is configured to supply fluidto the valves. A load sensing system is configured to determine a loadpressure value associated with each implement and to generate a signalcorresponding to the highest load pressure value determined. A controldevice is configured to allow selection of a first speed mode, a secondspeed mode, or a third speed mode. A controller is coupled to the pumpand to the load sensing system. The controller includes a speedadjustment portion configured to receive an input signal from thecontrol device corresponding to the selection, to modify a marginpressure value in response to selection of either the second mode or thethird mode, and to output the modified margin pressure value. Thecontroller is further configured to receive the signal corresponding tothe highest load pressure value determined and to adjust the fluidsupply from the pump based on both the highest load pressure value andthe modified margin pressure value.

According to another exemplary embodiment, a controller for adjustingthe operating speed of a movable implement on an industrial task machineincludes a speed adjustment module and a pump control module. Thecontroller is configured to receive a speed adjustment mode signal froma control device and receive a load pressure value signal associatedwith the movable implement. The speed adjustment module is configured toobtain a margin pressure value and to modify the margin pressure valuein response to the speed adjustment mode signal. The pump control moduleis configured to generate a pump pressure request based on the loadpressure value and the margin pressure value and to transmit the pumppressure request to modify an output of a pump.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects and features of various exemplary embodiments will be moreapparent from the description of those exemplary embodiments taken withreference to the accompanying drawings, in which:

FIG. 1 is a perspective view of an exemplary industrial machineillustrated as a backhoe loader;

FIG. 2 is a schematic of a portion of an exemplary hydraulic system;

FIG. 3 is a flowchart of an exemplary speed adjuster;

FIG. 4 is a flow chart of an exemplary method of speed adjustment for ahydraulic system; and

FIG. 5 is a flow chart of an exemplary hydraulic system using a speedadjuster.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments are directed to systems and methods for adjustingthe movement speed of hydraulic components in industrial machines.Industrial machines can be vehicles or stationary devices capable ofperforming an industrial task such as mining, agriculture, construction,manufacturing, etc. An industrial machine typically includes one or morecomponents that cause movement or perform a task that can be generallyreferred to as an active component, moveable implement, or arm. FIG. 1shows an exemplary industrial machine illustrated as a backhoe loadervehicle 10 able to perform different operations related to digging andthe movement of dirt or other materials.

A vehicle 10 includes a number of task performing implements. Forexample, a loader 12 coupled to a frame 14 of vehicle 10 can lift andcarry materials in a loader bucket 16 coupled to support arms 18. Thesupport arms 18 and the loader bucket 16 can be raised or loweredrelative to the frame 14 by one or more hydraulic actuators 20A and theloader bucket 16 can be moved relative to the support arms 18 by one ormore hydraulic actuators 20B. A backhoe can be used to dig trenches andmove material through the movement of a boom arm 22, a dipper arm 24,and a backhoe bucket 26. The backhoe bucket 26 is moveably coupled tothe dipper arm 24, which is moveably coupled to the boom arm 22, whichis moveably coupled to the frame 14. The boom arm 22 is rotatablerelative to the frame 14 in a first and second direction 30, 32controlled by one or more hydraulic actuators (not shown). The dipperarm 24 is rotatable relative to the boom arm 22 in a first and seconddirection 34, 36 controlled by one or more hydraulic actuators 38. Thebackhoe bucket 26 is rotatable relative to dipper arm 24 in a first andsecond direction 40, 42 controlled by a hydraulic actuator 44. Aplurality of ground engaging or traction devices 46 are connected to theframe 14 for movement of the vehicle 10. Frame 14 can also be stabilizedin a single location by one or more stabilizer arms 48. One or morecontrol devices are positioned in a cab or operator compartment 50 toallow a user to control the movement of the implements and the vehicle10. The operator compartment 50 is shown as an enclosed compartment, butcan be open or partially enclosed.

Each of the hydraulic actuators 20, 38, 44 is illustratively shown as ahydraulic cylinder that includes a moveable piston and rod. As would beunderstood by one of ordinary skill in the art, the position of the rodis adjustable by the introduction and/or removal of hydraulic fluid to arespective side of the piston within the hydraulic cylinder. Further,the rate at which the rod is moved is determined by the rate hydraulicfluid is introduced or removed from a respective side of the piston.

FIG. 2 is a partial schematic of an exemplary embodiment of a hydraulicsystem 100 configured to supply fluid to implements in an industrialmachine. A basic layout of a portion of the hydraulic system 100 isshown for clarity and one of ordinary skill in the art will understandthat different hydraulic, mechanical, and electrical components can beused depending on the machine and the moveable implements. The hydraulicsystem 100 includes a pump 102 that receives fluid from a reservoir 104and supplies fluid to one or more downstream components. For example,the pump 102 is in fluid communication with one or more valves 106 andeach valve 106 is in fluid communication with at least one actuator 108.A load sensing system 110 is included in or connected to the valves 106and uses one or more load sensing components 112 to monitor the loadpressure of the actuators 108. A controller 114 is coupled to the pump102, the load sensing system 110, and a control device 116 and isconfigured to adjust the pump output based on one or more inputs.

The exemplary embodiment depicted in FIG. 2 shows three valves 106A,106B, 106C, three actuators 108A, 108B, 108C, and three load sensingcomponents 112A, 112B, 112C, although any number of valves 106,actuators 108, and load sensing components 112 can be used. A one-to-onerelationship is shown for the valves, 106, actuators 108, and loadsensing components 112, but more than one actuator 108 can be associatedwith each valve 106, more than one valve 106 associated with eachactuator 108, and more than one load sensing component 112 can beassociated with each valve 106, as would be understood by one ofordinary skill in the art.

The pump 102 is configured to discharge fluid to the valves 106. Therate of the fluid discharged from the pump 102 adjusts the pressure ofthe fluid supplied to the valves 106 and the actuators 108. The pump 102can be capable of providing an adjustable output, for example a variabledisplacement pump or variable delivery pump, that is controlled based ona signal from the controller 114. A fixed displacement pump can also beused with different relief or unloading valves to effectively create avariable output. The pump 102 receives fluid, for example hydraulic oil,from the reservoir 104 and discharges fluid at the requested flow rateto create a desired system pressure.

The type of valve 106 can depend on the actuators 108 and the type ofmachine. Each valve 106 can be coupled to a hydraulic line to receivefluid from the pump 102 and one or more hydraulic lines to send fluid toone or more actuators 108. Although not shown, the valves 106 can beconfigured to receive a signal from the controller and/or one or morecontrol devices to selectively supply fluid to the actuators 108 basedon a user's commands. A basic schematic of the valves 106 is shown forclarity and one of ordinary skill in the art will understand that thevalves 106 can comprise a system of one or more different types ofvalves, sensors, comparators, switches, regulators, and other hydrauliccomponents including spool valves, check valves, solenoids, etc., thatare controlled by various hydraulic, mechanical, or electric signals.

The actuators 108 can be similar to the actuators 20,38, 44 describedabove or may be any other suitable type of hydraulic actuator known toone of ordinary skill in the art. FIG. 2 shows an exemplary embodimentof three double-acting hydraulic actuators 108A, 108B, 108C. Each of thedouble-acting actuators includes a first chamber and a second chamberand fluid is selectively delivered to the first or second chamber by theassociated valve 106 to move the actuator in a corresponding direction.The actuators 108 can be in fluid communication with the reservoir 104so that fluid leaving the actuators 108 drains to the reservoir 104.

In an exemplary embodiment, each of the actuators 108 controls theoperation of a respective moveable implement. Exemplary moveableimplements can include the loader bucket 16, moveable arms 18, boom arm22, dipper arm 24, and/or backhoe bucket 26 of the vehicle 10 shown inFIG. 1. In one embodiment, two actuators 108 control the same implement.One example is the raising of support arms 18 which includes an actuatorfor each of the two support arms 18 (only one shown). In anotherembodiment, the actuators 108 control separate implements. One exampleis where the actuator 108A controls the raising and lowering of dipperarm 24 and the actuator 108B controls the movement of backhoe bucket 26.The type of implements will depend on the type of industrial machine andthe tasks to be performed.

During use, each implement can create a variable load on the associatedhydraulic actuator 108 and the hydraulic system 100 can be pressurecompensated by the load sensing system 110 to account for the variableloads. The load sensing system 110 determines the load requirements ofone or more of the implements and creates a load pressure value that isused to adjust the pump output. In an exemplary embodiment, a loadsensing component 112 is associated with each of the valves 106 tomeasure the load, or pressure requirements, on the valves 106 from theactuators 108. The load sensing components 112 can be incorporated intothe valves 106 or in communication therewith. For example, the loadsensing component 112 can include one or more shuttle valves or isolatorvalves in communication with the main valves 106. The shuttle valvedetermines the highest pressure of two inlet pressures and sends asignal of the highest pressure to a new location. Certain systems canuse a single shuttle valve associated with each actuator, while othersystems can utilize a set of primary shuttle valves and a set ofsecondary shuttle valves. The primary shuttle valves determine thehighest pressure associated with an actuator, for example extending orretracting in a double actuating cylinder, and output the higherpressure. The secondary shuttle valves are used to select the highestpressure from more than one valve 106. Accordingly, there can be onefewer secondary shuttle valve than there are primary shuttle valves. Theload sensing components 112 can utilize other hydraulic, mechanical,electrical, and/or electromechanical devices and methods to determineand output the load pressure value to the controller 114.

The controller 114 can include any suitably programmed processor orcomputer that is capable of receiving and processing data and sendingappropriate commands. The controller 114 can have multiple inputs andoutputs as required. The controller 114 can be capable of operatingautomatically based on the inputs and also based on a manual input fromthe control device 116. The control device 116 can be positioned in anoperator compartment 50 and can include one or more buttons, switches,levers, pedals, joystick, or other user manipulated devices.

In addition to the load pressure requirements, the controller 114 can beconfigured to compensate for a margin pressure. The controller 114 caninstruct the pump 102 to deliver extra pressure above the required loadpressure referred to as the margin pressure value. The margin pressurevalue can be based, for example, on the pressure loss through thesystem, or an estimated pressure loss. The margin pressure can also beused to assist in controlling the delivery rate of the pump to morequickly accommodate a pressure change or excess pressure demand.

The controller 114 receives the load pressure value from the loadsensing system 110 and obtains the margin pressure value. These twovalues are then combined to achieve a pump output or flow rate. Thecontroller 114 can obtain the margin pressure value in a number of ways.For example, the margin pressure can be: a predetermined value that isbuilt into the controller 114, stored in memory, or received from alookup table containing different values based on different operatingparameters of the machine or vehicle; an adjustable value controlled bya user, technician, dealer, manufacturer etc.; a measured valve thatfluctuates based on the use of components in the hydraulic system and/orexternal influences such as temperature; or any combination thereof. Oneof ordinary skill in the art would understand other ways of establishingthe margin pressure value.

According to an exemplary embodiment, a speed adjuster 120 is capable ofmodifying the margin pressure value in response to an input from thecontrol device 116 as shown in FIG. 3 with the method steps described inFIG. 4. For example, the controller 114 receives the load pressure value(step 202) and the control device 116 can allow a user to select a speedadjustment mode (step 204). In the speed adjustment mode, the speedadjuster 120 obtains the margin pressure value (step 206). The marginpressure value can be obtained from the controller 114, or it can beobtained by the speed adjuster 120 using any of the methods describedabove. The speed adjuster 120 modifies the margin pressure value (step208) to increase or decrease the margin pressure in response to the userselection. In an exemplary embodiment a calculation is performed usingthe standard valve margin pressure and an increase or decrease speedrequest. The controller 114 combines the modified margin pressure valuewith the load pressure value (step 210) to obtain a pump output pressureas shown in FIG. 3. The controller 114 then produces a signal to modifythe pump output (step 212). In an exemplary embodiment, the output is amodified pump load sense pressure value creating a modified pump output.Because the pressure generated by the pump 102 directly affects themovement speed of the hydraulic actuators, and thus the moveableimplements, decreasing or increasing the margin pressure value canadjust the movement speed of all the moveable implements associated withthe pump 102. The speed adjuster 120 can be incorporated in thecontroller 114, for example as a device, module, control algorithm,logic program, or other software, or the speed adjuster 120 can be aseparate and independent device with a processor and memory incommunication with the controller 114, the pump 102, or othercombinations of components.

The type of control signal and how the pump 102 is adjusted will varydependent on the system. For example, a control signal can be sent fromthe controller 114 directly to the pump 102 or a pump controller, acontrol signal can be sent from the controller 114 through a valve inthe load sensing system 110, or a control signal can be sent from thecontroller 114 through a load sense generation valve (not shown) andpump load sensor. The control signal can be electrical, hydraulic,mechanical, or any combination thereof. In an exemplary embodiment, anelectrical signal is sent to a valve which is hydraulically connected tothe pump 102.

FIG. 5 shows an exemplary embodiment of a hydraulic system utilizing aspeed adjuster. The system includes an actuator 302 receiving fluid froma main control valve 304. The main control valve 304 includes a loadsensing system that submits a load sense request 306 to a controller308. If desired, a user implements a speed mode request 310 triggering aspeed mode calculation 312 based on the speed mode request 310 and thevalve margin pressure 314. The speed mode calculation 312 modifies themargin pressure 314 based on the requested speed mode and outputs thecalculated valve to the controller 308. The controller 308 combines theload sense request 306 with the calculated speed mode value 312 tocreate a speed mode pressure request value that is translated into acurrent value using a pressure vs. current lookup table 316. Theresultant current is then output to a load sense generation valve 318that communicates with a hydraulic pump 320 to modify the flow from thepump outlet 322. The load sense generation valve 318 can be anelectro-proportional pressure control valve, for example a poppet-typehydraulic relief valve that can be infinitely adjusted across aprescribed range using a variable electric input from the controller308, where the pressure output is proportional to the current input.

Different operations can require different movement speeds. For example,certain operations, such as digging in close proximity to a pipe with abackhoe, require precision or fine control over the movement of thecomponents of a backhoe. As such, a high resolution of movement rates ofthe respective components would be desired. In another example, such asmoving dirt to a truck for removal, it is desired to provide a higherrate of movement of the components of the backhoe to reduce cycle times.As such, a lower resolution or gross resolution of movement rates wouldbe desired.

Accordingly, the speed adjustment mode can include a slow, or precision,mode that reduces the movement speed of the implements and a fast, orproductivity mode, that increases the movement speed of the implements.For example, the control device 116 has two discrete settings, a firstsetting corresponding to normal operation (gain=1) and a second settingcorresponding to slow or precision operation (gain<1). In anotherexample, the control device 116 has three discrete settings, a firstsetting corresponding to normal operation (gain=1), a second settingcorresponding to precision operation (gain<1), and a third settingcorresponding to fast or productivity operation (gain>1). In variousexemplary embodiments, the control device 116 has a plurality ofsettings or has a variable gain, such as in the case of an infinitelyadjustable control device 116.

In various exemplary embodiments the slow mode can be in the range ofapproximately 20% to approximately 100% of the speed of the normal mode,although the slow mode can be configured down to just above 0% of thenormal mode if needed. In various exemplary embodiments the slow modecan be approximately 50% or approximately 55% of the speed of the normalmode. In various exemplary embodiments the fast mode can be in the rangeof approximately 100% to approximately 200% of the speed of the normalmode. In various exemplary embodiments the fast mode is approximately120% or approximately 130% of the speed of the normal mode. In variousexemplary embodiments the amount of speed adjustment can be selected bya user up to approximately 200% of the normal mode.

The reduction of movement speed and reduction of margin pressure canvary depending on the system. As such, the reduction in movement speedand the reduction in margin pressure are not necessarily linear, i.e. a50% reduction of speed does not necessarily equal a 50% reduction in themargin pressure.

By altering the margin pressure, the system can effectively reduce orincrease the movement speed of one or more moveable implements withoutthe use of complex electro-hydraulic valves.

The foregoing detailed description of the certain exemplary embodimentshas been provided for the purpose of explaining the general principlesand practical application, thereby enabling others skilled in the art tounderstand the disclosure for various embodiments and with variousmodifications as are suited to the particular use contemplated. Thisdescription is not necessarily intended to be exhaustive or to limit thedisclosure to the exemplary embodiments disclosed. Any of theembodiments and/or elements disclosed herein may be combined with oneanother to form various additional embodiments not specificallydisclosed. Accordingly, additional embodiments are possible and areintended to be encompassed within this specification and the scope ofthe appended claims. The specification describes specific examples toaccomplish a more general goal that may be accomplished in another way.

As used in this application, the terms “front,” “rear,” “upper,”“lower,” “upwardly,” “downwardly,” and other orientational descriptorsare intended to facilitate the description of the exemplary embodimentsof the present disclosure, and are not intended to limit the structureof the exemplary embodiments of the present disclosure to any particularposition or orientation. Terms of degree, such as “substantially” or“approximately” are understood by those of ordinary skill to refer toreasonable ranges outside of the given value, for example, generaltolerances associated with manufacturing, assembly, and use of thedescribed embodiments.

What is claimed:
 1. An industrial task machine comprising: a mechanicalarm; a hydraulic actuator coupled to the mechanical arm to move the armbetween a first position and a second position; a valve in fluidcommunication with the hydraulic actuator for supplying fluid to thehydraulic actuator; a pump configured to discharge fluid to the valve; aload sensing system configured to determine a load pressure valueassociated with the mechanical arm; a control device configured topermit selection of a normal mode or a speed adjustment mode; a speedadjuster configured to receive an input from the control device, modifya margin pressure value in response to selection of the speed adjustmentmode, and output die modified margin pressure value; and a controllercoupled to the pump, the load sensing system, and the speed adjuster,the controller configured to receive the load pressure value from theload sensing system and the modified margin pressure value from thespeed adjuster, and adjust the fluid discharge from the pump based onboth the load pressure value and the modified margin pressure value. 2.The machine of claim 1, wherein the speed adjustment mode includes aslow mode and a fast mode, each of which is independently selectable,wherein selection of the slow mode reduces a movement speed of themechanical arm and selection of the fast mode increases the movementspeed of the mechanical arm.
 3. The machine of claim 2, wherein thespeed adjuster reduces the margin pressure value in response toselection of the slow mode and increases the margin pressure value inresponse to selection of the fast mode.
 4. The machine of claim 2,wherein in the slow mode the movement speed is reduced by approximately50% relative to operation in the normal mode.
 5. The machine of claim 2,wherein in the fast mode the movement speed is increased byapproximately 20% relative to operation in the normal mode.
 6. Themachine of claim 1, wherein the speed adjuster calculates the modifiedmargin pressure value based on a predetermined margin pressure.
 7. Themachine of claim 1, wherein the mechanical arm comprises a swing arm, aboom arm, or a crowd arm.
 8. The machine of claim 1, wherein the speedadjuster is incorporated into the controller.
 9. An industrial taskmachine comprising: a frame; a plurality of movable implements coupledto the frame, each implement individually moveable between a firstposition and a second position; a plurality of hydraulic actuators,wherein at least one hydraulic actuator is coupled to each of theimplements; a plurality of valves, wherein at least one valve is coupledto each hydraulic actuator; a pump configured to supply fluid to thevalves; a load sensing system configured to determine a load pressurevalue associated with each implement and to generate a signalcorresponding to the highest load pressure value determined; a controldevice configured to allow selection of a first speed mode, a secondspeed mode, or a third speed mode; and a controller coupled to the pumpand to the load sensing system, wherein the controller includes a speedadjustment portion configured to receive an input signal from thecontrol device corresponding to the selection, to modify a marginpressure value in response to selection of either the second mode or thethird mode, and to output the modified margin pressure value, thecontroller further configured to receive the signal corresponding to thehighest load pressure value determined and to adjust the fluid supplyfrom the pump based on both the highest load pressure value and themodified margin pressure value.
 10. The machine of claim 9, wherein inthe second mode, a movement speed of one of the plurality of movableimplements is in the range of approximately 20-100% of the movementspeed of the one of the plurality of movable implements in the firstmode.
 11. The machine of claim 9, wherein in the third mode, a movementspeed of one of the plurality of movable implements is in the range ofapproximately 100-200% of the movement speed of the one of the pluralityof movable implements in the first mode.
 12. The machine of claim 9,wherein operation in the second mode or in the third mode alters thespeed of all the movable implements of the plurality of movableimplements.
 13. The machine of claim 9, wherein a first movableimplement of the plurality of movable implements includes a boom arm anda second movable implement of the plurality of movable implementsincludes a bucket.
 14. The machine of claim 9, wherein the controldevice includes a user interface for selecting the first mode, thesecond mode, or the third mode.
 15. A controller for adjusting theoperating speed of a movable implement on an industrial task machine,the controller comprising: a speed adjustment module; and a pump controlmodule, wherein the controller is configured to receive a speedadjustment mode signal from a control device, and receive a loadpressure value signal associated with the movable implement, and whereinthe speed adjustment module is configured to obtain a margin pressurevalue and to modify the margin pressure value in response to the speedadjustment mode signal, and wherein the pump control module isconfigured to generate a pump pressure request based on the loadpressure value and the margin pressure value and to transmit the pumppressure request to modify an output of a pump.
 16. The controller ofclaim 15, wherein the speed adjustment mode signal represents either aslow mode or a fast mode, wherein operation in the slow mode correspondsto a reduction of the movement speed of the moveable implement andwherein operation in the fast mode corresponds to an increase of themovement speed of the moveable implement.
 17. The controller of claim15, wherein the pump pressure request is transmitted to a valve in fluidcommunication with the pump.
 18. The controller of claim 15, wherein themargin pressure value is a predetermined value.
 19. The controller ofclaim 15, wherein the pump pressure request includes an electronicsignal.
 20. The controller of claim 17, wherein the moveable implementis powered by a hydraulic actuator in fluid communication with thevalve.